Typical thermal conductivity values of plastics range between 0.600 W/m-K down to around 0.150 W/m-K depending on the type of polymer. Compared to metals that range from 200 W/m-K to 15 W/m-K and ceramic borosilicate glass that is around 1 W/m-K, plastics are good heat insulators. On the other hand, compared to cellular solids such as polyurethane and polystyrene foams which have thermal conductivity values around 0.025 W/m-K, plastics are remarkable heat conductors. Therefore on a material basis, it can be concluded that plastics are neither terrific conductors of heat nor great heat insulators. Similarly in the case of mechanical strength, structural plastic materials fall between metals and foams in strength and modulus. There is a significant advantage to be gained in the thermoplastics industry if plastics could be easily made into better heat insulators since in many applications heat flow is not desired and the mechanical properties of cellular solids are not acceptable. Polymers also typically do not perform well at low temperatures or under cryogenic conditions due to their brittleness at these temperatures. Therefore, metals are usually used instead of plastics in cryogenic conditions due to their better performance at low temperatures. Since polymers are much lighter in weight compared to metals, as well as being easier to process, improving thermal performance properties of plastics would be economically and industrially preferred for such applications. New polymer compositions with improved physical properties for certain applications are needed.